South Asian Bat Monitoring Programme
Pteropus giganteus Population Monitoring Project
The South Asian Bat Monitoring Programme aims to create awareness
about bat conservation issues, involve and educate biologists and
nature-lovers in studies about the biology of bats, and establish a
conservation action plan. The Programme will initially focus on one
species, the Indian flying fox (Pteropus giganteus) as it is
the most known and recognizable bat species in South Asia.
The Program is based on a collection of volunteers from a broad
range of backgrounds who have identified Pteropus roosts in their
area and have committed to studying the roost and obtaining
population information on a regular basis. It consists entirely of
volunteers and is the first such network to monitor the population
of a species in South Asia. The information from all these sites
will be compiled and analyzed for trends in the population of Pteropus
giganteus, identify key threats to roosts and provide
recommendations for their conservation.
||Little is known about the population status of Pteropus or
any other bat species in any country of South Asia. While we
have a good idea of the number of species, and limited
information about their distribution, the actual numbers of
individuals of each species remain an unknown.
||It is difficult to assess whether a species requires any
conservation measures without reliable population estimates.
That is, unless one cannot show that a population is
declining or under threat of decline, one cannot create a
plan to conserve it.
||Although there are anecdotal accounts which indicate that
populations and roosts of many bat species are decreasing,
there is no hard evidence. There is thus an urgent need to
assess the populations of bats and to monitor them on a
regular basis to determine population trends.
||Bat populations face some of the same threats that other
species do, including direct disturbance by humans, habitat
loss, and limited roosting sites.
||Pteropus giganteus, the Indian flying fox, is an
ideal first candidate to study population trends because it:
||is the only large pteropodid on the subcontinent
and is easily identified
||is visible during day
||is large and easy to count
||often roots near humans
||is often easy to acquire historical information
about roost from locals (like age of roost,
behaviour of the animals and population trends)
||To establish an organised group of individuals that
monitors Pteropus roosts and provides information on
population size as well as threats.
||To have a significant number of participants throughout
||To establish long term data on roost size, fidelity, etc.
||To collate this information and analyze the data for
trends in populations
||To make this information readily available for
dissemination to all interested parties
||To create a conservation plan for Pteropus based upon the
The methodology requires three simple steps
||Locate and describe the roost site
|| Count the number of bats at this roost
||Provide the information via the printed or online form
(Minimum) - The following items are essential and necessary.
||Location (State, District, Taluka, Village)
||Protocol used to count bats: Exact or Estimate (see below)
(Additional) - The following are very useful, but not
absolutely necessary. Participants are encouraged to provide as much
as possible, without making the task of monitoring too difficult.
||GPS Location of roost site (Degrees-Minutes-Seconds or
||Number of roost trees
||Roost tree species (common or scientific name)
||Height of roost (range)
||Photographs of the roost (showing details as well as
||If roost is remote, directions from nearest village
||Distance to nearest forest and directions
||Threat information (e.g., disturbance, killings, habitat
||Protection information (e.g., temple, sacred groves,
||Notes and comments (include any anecdotal information
about history of roost)
||Observer's Email and Phone number
Measuring the population
Each roost should be measured by means of one of two methods, an
exact count or an estimated count. The choice of methodology should
be noted on the data sheet.
Bats tend to be more active during dusk and dawn hours, often flying
around the roost and changing their location. It is therefore best
to conduct the count during the day (not dusk or dawn) as this
minimizes the chance of missing a bat in the count or multiple
counts of the same individual.
||Exact Method: This method should be used for small
roosts (300 or less) where individuals can be easily
distinguished and counted. Counts should be conducted by
enumerating the number of bats on individual branches to
create a tree total and then summing bats across all trees.
||Estimation Method: If there are too many bats to
count each and every bat, one can use an estimation method.
It is important to note that no one method is suitable for
all situations. Here we present a few methods that are
commonly used to estimate populations. If you use your own
estimation method, or a variation of one of these, please
describe in detail on the form.
||Branch Estimates: Identify all the major
branches on the tree that have bats on them. Pick a
branch that has an average number of bats on it
(i.e., don't pick one that has just a few, or the
branch that has the most). Count the number of bats
on this branch and multiply that number by the total
number of branches that are occupied by bats.
- You can make this estimate more precise by
counting a few branches and taking the average,
and also by ensuring that the branches are of
roughly equal length.
- Additionally you could count the actual number
of bats on branches where they are sparse, and
then use the estimation methods for the heavily
||Tree Estimates: In situations where the
roost is spread out across many trees, one can count
the number of bats on a tree and then multiply by
the number of trees. You can increase the accuracy
by following the same suggestions above.
||Flight Estimates: If it is not possible to
count the bats while they are on the trees, one can
count the number flying from the roost. This is
suitable for small roosts where visibility is not a
problem. This methods is not recommended as many
factors can affect this count (bats flying in
different directions, darkness affecting visibility,
inaccuracy of counting many flying bats
Ideally, censuses should be done once a month. At a minimum a census
should be done annually. However, annual censuses will not provide
useful information on seasonal patterns of movement, changes in
roost size or reproductive cycles.
Roost ID numbers
Each roost will be assigned a unique roost ID - preferably based on
a GPS location but if not possible then by using the detail
directions to and description of the roost. Once your roost site has
been given a number, you may use this reference number in subsequent
surveys and not have to fill in the location information every time.
Disturbance at Roosts
It is important that the monitoring activity of the researcher not
disturb the bats at their roost. One should avoid any activity, such
as getting too close to the trees or talking too loud, which may
disturb the bats.
There are many other studies that can be done at the roost site, and
much depends on the time and inclination of the participant. Some of
the possible topics worth studying include monitoring roosts for sex
ratios, age structure, reproductive status, threats, social
behavior, sleeping activity, social structure, foraging activity,
movement between trees/roosts, direction that bats fly at sunset,
etc. Those interested in studying such aspects of the roost may wish
to contact the group organizers for details.
The data collected will be analyzed for patterns and changes in
populations. Annual reports will be sent to each participant in the
network as well as published online. The summary information, but
not the details of each site, will also be available at any time via
the internet. The network will periodically publish summaries of the
information collected so as to distribute the information to the
scientific community and also inform policy.
Ownership of Data / Copyright Issues
Ownership of Data
The data collected belong to the researcher and the group. Thus, the
individual volunteer may use their site data to publish in any way
they wish and the Programme may use the data from multiple sites for
"Programme scale" publications.
Thus, by participating in this group, the volunteer agrees to help
the Programme to
||Add their data to the Programme database
||Present summaries of the data on the website as well as in
annual printed summaries
(Note: at no point will the Programme release actual
location information or details of a study to others without
the participant's permission)
||Publish papers based on the information collected by the
Programme. These papers would be at the scale of the entire
Programme and not the individual sites. Thus there should be
no overlap between these publications of those of individual
researchers. If anything, they will compliment each other.
Since we anticipate that there will be many individuals
taking part in this collaborative project, it would be
difficult to list all as authors.
Sanjay Molur and Shahroukh Mistry, Coordinators
Sally Walker, Convenor / Administrative Chair, CCINSA
Sripathi Kandula, Scientific Chair, CCINSA
CCINSA - Zoo Outreach Organization
96, Kumudham Nagar, Vilankurichi Road
Coimbatore, Tamil Nadu 641035, India
Ph: +91 422 2665298, 2665450
Fx: +91 422 2665472